1. Field of the Invention
The present invention relates to a measurement method, and particularly a method for measuring propagation loss in a plane light guide plate.
2. Description of the Related Art
Optical plane light guide plates are of great importance to application of optical technology, especially of the field in opto-electronic display. Such issues are discussed in US Patent Publication No. 2005/0084228 A1, US Patent Publication No. 2009/0316072 A1US Patent Publication No. 2011/0069510 A1 and U.S. Pat. No. 7,325,960 B2. Recently, optical plane light guide plates are used in chemical reactors of photocatalysts, as driving elements in the chemical reactors or in platforms for chemical reactions. Thus, coupling efficiency of and propagation loss inside the optical plane light guide plates is the key threshold of related technologies.
On the other hand, the problems of environmental pollution are getting much worse in recent years, and thus the removal of pollutants using methods of photocatalysts or photochemistry is potentially developmental and significantly meaningful. Generally, photocatalyst particles and reaction solution are mixed homogeneously during the processes of photocatalytic reduction reaction such that the photocatalyst suspending in the reaction solution can carry out photocatalytic reduction effectively. Such reaction systems of mixing the photocatalyst particles with the reaction solution take advantage of high efficiency of reaction. However, the photocatalysts are needed to be recycled from the reaction solution, and thus the complexity, time and costs of the processes increase. Additionally, it is still doubted how to make the photocatalyst have sufficient illuminated area in order to carry out photocatalytic reaction for mass production. In 1977, Marinangeli and Ollis proposed an idea of optical fiber photocatalytic reactor. For such reactors, TiO2 photocatalyst is coated on the surface of the optical fiber, and the reactants are attached to the surface of TiO2 film. The reaction light source propagates in the optical fiber such that the TiO2 photocatalyst and input lights can perform the photocatalytic reduction. As described in U.S. Pat. Nos. 5,875,384, 5,919,422 and 6,238,630, the efficiency of the reactions of the light-guided photocatalytic reactors with small volumes is good, but the reactors are required to fix in reaction tanks resulting in lower efficiency of mass transfer of reactants.
Thus, TW Patent Application No. 096107772 and U.S. Pat. No. 7,927,553 both disclose a photocatalytic reactor with movable conformal light guiding plate to accelerate the processing of the photocatalytic reaction. In other aspect, plane light guide plates are used as a propagation interface for the light to induce or enhance the photochemical reactions in such reactors mentioned above, in order to eliminate the loss of absorption or scattering of the light used in the processes, and achieve the optimal design of photochemical reactors.
Accordingly, the present invention provides a method for measuring propagation loss in a plane light guide plate for applications of photoelectronic detection technologies as well as chemical engineering, environmental engineering and other green technologies, to solve the difficulties of prior arts and meet the demands.